The Roles of Competition and Facilitation in Producing Zonation Along an Experimental Flooding Gradient: a Tale of Two Tails with Ten Freshwater Marsh Plants

Daniel Campbell,Paul Keddy

doi:10.1007/s13157-021-01524-4

Abstract

The Roles of Competition and Facilitation in Producing Zonation Along an Experimental Flooding Gradient: a Tale of Two Tails with Ten Freshwater Marsh Plants

Highlights

The zonation of plants along wetland gradients is widespread and well-described (Keddy 2010)
The primary objective of this experiment was to test for effects of competition and facilitation upon plant zonation along a gradient of flooding stress, and only flooding stress, without interference from other environmental stresses
The experiment was designed to evaluate the generality of previous work on competition along gradients and to evaluate the Stress Gradient Hypothesis (SGH) hypothesis, which hypothesizes an important role for facilitation (Bertness and Callaway 1994; He et al 2013)

Summary

Introduction

The zonation of plants along wetland gradients is widespread and well-described (Keddy 2010). The simplest explanation is the oldest: that changes in species composition along a gradient are a direct consequence of changes in physical stresses, such as flooding or salinity, that act directly upon plant growth (e.g., Penfound and Hathaway 1938; Chabreck 1972). Field and lab experiments have repeatedly shown that species interact along these same physical stress gradients through competition, facilitation and even herbivory (e.g., Pennings and Callaway 1992; Bertness and Hacker 1994; Grace and Ford 1996), and these interactions contribute to plant zonation. The Stress Gradient Hypothesis (SGH) summarizes these interactions and theorizes that competition among plants is important in habitats with low environmental stress, while facilitation is more important where high physical stress or high consumer pressure prevail (Bertness and Callaway 1994). The SGH has broad support (He et al 2013)

Methods

Results

Conclusion